Scan the list of winners at Thursday's Americana Music Association Honors & Awards show, and you might think you've stumbled into a rock 'n' roll time warp. Among the night's top honorees at one of Nashville's hippest, most genre-bending awards shows after all, were former Led Zeppelin lead singer Robert Plant and the Band drummer Levon Helm.

The three-hour ceremony, which also featured performances by lifetime achievement honorees Jason and the Scorchers, Joan Baez and John Hiatt, included actor/musician Billy Bob Thornton and his bandmates, the Boxmasters, presenting the Artist of the Year award to Helm. At the close of the show, Helm and several of the award recipients offered a musical tribute to President's Award winner Jerry Garcia, of the Grateful Dead.

In one of the evening's more comical moments, Robert Plant, who took the stage to pick up two awards with Alison Krauss for their collaborative effort, 'Raising Sand,' recalled playing with his "other band" in Nashville "thirty or forty years ago," during which they received the key to the city, then were quickly put under house arrest. He added, jokingly, that the incident may not have happened in Nashville after all, but in some other city.

The awards show is the centerpiece of the Americana Music Association's four-day conference, attended by radio programmers, music-industry professionals and fans of the rapidly-growing music format from all over the world.